Many vessels are provided with openings or manways for gaining access to the interiors of the vessels. An axially facing seat or sealing surface may surround the manway on the interior of the vessel for cooperation with a closure that is manipulated from outside the vessel to seat against the sealing surface.
In use, such sealing surfaces may become worn or pitted so that leakage results. When this happens, it is necessary to reface the sealing surface. However, the location of the sealing surface on the inside of the vessel makes this task difficult to perform. At one time, the entire device or section was replaced, at considerable expense and loss of time, or the sealing surface was repaired by welding or other measures. Neither of these measures was satisfactory.
The difficulty of refacing such surfaces is even greater when the opening is not round, as, for example, when the manway is elliptical in shape.
In an effort to solve the problems associated with repair of such surfaces or seats, various tools have been developed to resurface the seat in situ. These have included portable resurfacing tools such as described in U.S. Pat. No. 2,472,374, for example. The device described in this patent is inserted through the opening from outside the vessel and secured in place so that a cutting bit 30 is positioned to move across the face of the seat a' to resurface it as the tool is rotated in the opening. Movement of the bit across the seat is effected by cooperation between a follower pin 32 and elliptical cam groove 15. In addition, the bit may be moved radially inwardly and outwardly across the seat by fluid pressure in piston 50 acting in opposition to spring 52. The tool is located and held in the opening by plungers 80 and feet 91.
The tool described above is manually operated and is especially adapted for resurfacing the seat around small openings, such as hand holds and the like.